Wayne, As you suggested, because this is a new service, a PV service disconnect is required. The question of whether a second disconnect is required, a new disconnect for the main service, is a Code issue, as far as I can tell. It is also an interpretation, but I¹ll get to that later.
It just so happens that the June/July issue of SolarPro magazine will have an extensive article on making PV interconnections. The authors are Ryan LeBlanc and Tarn Yates from SPG Solar. From their article, here are some Code articles that apply to selecting and locating a disconnect for a line side connection: 230.66 Disconnect shall be listed for use as service equipment. 230.70(A)(1) Disconnect shall be installed at a readily accessible location. 230.72(A) All service disconnects shall be grouped together. The last article is no doubt the one that the AHJ is referencing in this case. The reason I feel that this extra expense and effort is an interpretation, as much as it is a Code issue, is that you could make a load side connection and still have the math work for the feed-in tariff program and for the revenue metering. How is that? Well, a meter on the inverter output circuits will read the total PV kWh for the feed-in tariff. A bi-directional meter for the revenue meter will read in-flow from the utility and out-flows to the utility. The difference between total PV kWh and the out-flow-kWh are the PV generated kWh that the customer used on site rather than export to the utility. Right? Whatever PV generated energy is not exported to the utility is used on site. So for billing purposes the customer is charged as follows: Total kWh for billing = In-flow kWh + (feed-in tariff kWh out-flow kWh) Theoretically, this can also be implemented affordably by the utility: move the exiting revenue meter to the PV system; add a $100 bi-directional meter to the original meter can. Finished. Making a line-side connection is often difficult and expensive, especially when you now have to add a new service disconnect for the facility. At least in theory, it is also dangerous; the fault-currents there are higher. You have these implementation issues on the one hand. On the other hand you have a spreadsheet, or a one-time fix the the utility¹s billing software. So I think the utility is making this more onerous than they need to. Especially for small generators, the cost of this service upgrade will kill the deal. The utility probably isn¹t interested in this solution, but we can still dream of the perfect fix. David Brearley, Technical Editor SolarPro magazine NABCEP Certified PV Installer david.brear...@solarprofessional.com Direct: 541.261.6545 Fax: 541.512.0343 Visit our Web site at solarprofessional.com On 3/9/09 5:25 PM, "Allan Sindelar" <al...@positiveenergysolar.com> wrote: > Wayne, > Use this as a tool: http://www.solarabcs.org/utilitydisconnect/ > and this: http://www.nrel.gov/docs/fy08osti/42675.pdf > > > Allan Sindelar > allan(at)positiveenergysolar.com <mailto:al...@positiveenergysolar.com> > NABCEP Certified Solar PV Installer > Positive Energy, Inc. > 3201 Calle Marie > Santa Fe NM 87507 > 505 424-1112 > www.positiveenergysolar.com > > Please consider the environment before printing this e-mail. > > -----Original Message----- > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Wayne Irwin > Sent: Monday, March 09, 2009 4:41 PM > To: re-wrenches@lists.re-wrenches.org > Subject: [RE-wrenches] Line Side Feed In and Disconnects > > Hello Wrenches, > > Here in Gainesville, Fla. we have recently adopted a Feed In Tariff. > So, now we are supposed to directly feed the line side of the utility meter > (essentially a new service). No big deal. > As usual we use an AC disco between the inverter and the grid. However, the > permit department is requiring that we install and additional disco between > the existing service feed and the distribution panel to group all disco's in > the same location. This especially adds an additional expense when dealing > with 3 phase systems as well as the raises the question, is this really the > National Electrical Code or just an interpretation? Your thoughts? > > Wayne Irwin, President > Pure Energy Solar International Inc. > Lic # CVC56695 > <mailto:pureenergyso...@hotmail.com> > > > > > Date: Mon, 9 Mar 2009 18:20:57 -0400 > From: reelli...@gmail.com > To: re-wrenches@lists.re-wrenches.org > Subject: Re: [RE-wrenches] Small Torque Wrench > > I got mine from "the knife and tool store" http://myworld.ebay.com/don19470/ > on E bay. nice tool, adjustable 10 - 50 In Oz and he has others, just get the > adapter that lets you use 1/4" drive bits and your good to go. It is a german > tool and i use it on all breaker connections as well as others. > > Later, > Bob > > On Mon, Mar 9, 2009 at 12:10 PM, Peter Parrish <peter.parr...@calsolareng.com> > wrote: >> >> >> We have a great torque wrench for snugging down module clamps, Sharp SRS >> bolts, etc. What do folks use to insure that wire terminals are torqued to >> spec? We¹re talking 1.1 to 3.3 N-m (10-30 in-lbs). I¹m imagining something >> compact like an over-sized screwdriver. >> >> - Peter >> >> Peter T. Parrish, President >> California Solar Engineering, Inc. >> 820 Cynthia Ave., Los Angeles, CA 90065 >> Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885 >> CA Lic. 854779, NABCEP Cert. 031806-26 >> peter.parr...@calsolareng.com >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm <http://www.re-wrenches.org/etiquette.htm> >> >> Check out participant bios: >> www.members.re-wrenches.org <http://www.members.re-wrenches.org/> >> >> >> >> >> >> Windows Live Groups: Create an online spot for your favorite groups to meet. >> Check it out. >> <http://windowslive.com/online/groups?ocid=TXT_TAGLM_WL_groups_032009> >> >> _______________________________________________ >> List sponsored by Home Power magazine >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Options & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out participant bios: >> www.members.re-wrenches.org >> >>
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